The following information is provided to assist the reader to understand the technology described below and certain environments in which such technology can be used. The terms used herein are not intended to be limited to any particular narrow interpretation unless clearly stated otherwise in this document. References set forth herein may facilitate understanding of the technology or the background thereof. The disclosure of all references cited herein are incorporated by reference.
Protective enclosures or guards are often used with sensors such as infrared (IR) gas sensors to protect the sensors from undesirable elements (for example, dust, dirt, moisture etc.) in the environment in which the sensor is used. Among other things, such protective enclosures or guards protect the analytical volume from the inflow of water, as a result of rain, wind, waves etc. It is desirable that the protective enclosure protect the sensor from undesirable elements in the environment while allowing for quick transfer of the measured gas from that environment to the analytical volume of the sensor.
In the case of many currently available protective enclosures or guards used in connection with gas sensors, the enclosure must be oriented in a preferred direction to achieve both optimal response time and water rejection. Proper orientation is typically achieved in such currently available protective enclosures by either built-in constraints on the sensor housing or through manual orientation by the user. As a result, the protective enclosure is typically fixed. Response time and/or water rejection are negatively impacted in a substantial manner if the protective enclosure deviates from its optimal orientation.
Regardless of the orientation of currently available enclosures, most such enclosures have a negative effect upon response time as a result of relatively large internal volumes encompassing the sensor.